How often should you reseal a commercial parking lot?

I’m trying to figure out the right maintenance schedule for the parking lots. One is 8 years old and starting to show some oxidation and hairline cracks, so I’m wondering when I should get it resealed.

A general contractor friend recommended Asphalt Coatings Company. He said they do a lot of commercial work around the Front Range and usually suggest resealing every 2–3 years depending on traffic and weather.

How often do you recommend resealing parking lots in Colorado or similar climates? Is every 2 years too much or is that about right?